It's こうなん, not こんあん, but apparently the hepburn romanization of こう (and other long vowels within the same morphene) is "supposed" to be represented by the accen

It's こうなん, not こんあん, but apparently the hepburn romanization of こう (and other long vowels within the same morphene) is "supposed" to be represented by the accent macron (like "kō"), according to wikipedia: https://en.wikipedia.org/wiki/Hepburn_romanization https://en.wikipedia.org/wiki/Hepburn_romanization Sounds like there's variation here, however -- see the picture of the railroad sign in the wikipedia article, which is a mishmash of different approaches. I don't tend to dwell on romanization of words, because I just go to hiragana when there's doubt (which was my point).